Comparison of the Measurement Accuracy of Material Sample Specular Reflection Coefficient for Two Types of Measuring Facilities

Author(s):  
Sergey A. Fedorov ◽  
Nikolay L. Menshikh ◽  
Ruslan V. Gilmutdinov ◽  
Vladimir S. Solosin
2021 ◽  
pp. 44-50
Author(s):  
Ruslan V. Gilmutdinov ◽  
Igor I. Krasnolobov ◽  
Nikolay L. Menshikh ◽  
Sergey A. Fedorov

This paper is discussed two methods for measuring the bistatic scattering characteristics of flat samples of the material. The experimental studies and numerical simulations of the dependence of the specular reflection coefficient on the incident angle of wave on a flat material sample carried out in the bistatic scheme of the experiment (rotation of the receiving and transmitting antennas) and in the monostatic scheme using a dihedral corner reflector (rotation of the object). Measurements for the magnetodielectric flat sample were carried out in ITAE RAS on two test facilities with the corresponding scheme of the experiment. To identify the errors of the methods used, we carried out numerical simulations of the measurement of the specular reflection coefficient of the sample under test by the method of integral equations (method of moments) in the FEKO program in the formulation of two experimental schemes. The obtained results were compared with each other and with the results of analytical calculations of the specular reflection coefficient carried out using the Fresnel formulas when considering an infinite flat layer of material. These calculations make it possible to compare the methodical errors in measuring the reflection coefficient in the two considered experimental schemes. It was shown that the results of the measurements using the corner reflector give methodical errors (deviations from the analytical calculation) by 1–2 dB more than the measurements on the bistatic facility. The results of experiments and numerical simulations are in agreement with each other. The conclusions obtained in this work are applicable to any experimental facilities for the study of planar materials.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jingchen Wang ◽  
Eng Gee Lim ◽  
Mark Paul Leach ◽  
Zhao Wang ◽  
Ka Lok Man

An open-ended coaxial cable is used to measure the dielectric properties of lossy liquid. The method which is based on the measurement of the reflection coefficient of the open-ended cable makes it easy to operate and postprocess. To meet the accuracy requirements, the dimensions of the coaxial cable need to be taken into consideration; therefore, it is necessary to select an appropriate coaxial cable for the measurement. This paper investigates the influence of cable dimensions on dielectric measurement accuracy. With careful choice of the coaxial cable, the relative error of calculated results can be less than 0.1%.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3241
Author(s):  
Xiaoxin Chen ◽  
Chen Li ◽  
Liangjin Chen ◽  
Hui Wang ◽  
Yiming Zang ◽  
...  

Partial discharge (PD) leads to the generation of electrical, acoustic, optical, and thermal signals. The propagation characteristics of optical signals in gas insulated metal-enclosed transmission lines (GIL) are the basis of optical detection research. This paper simulates the propagation of PD optical signals in GIL through modeling GIL with different structures and specification parameters. By analyzing the optical parameters on the probe surface and the detection points when the PD source position is different, the influence of the difference in specifications caused by the voltage level on the propagation of the GIL PD optical signal is studied. The results show that the GIL cavity structure will affect the faculae distribution and the relative irradiance (RI) of the detection surface; the PD source position has a huge impact on the faculae distribution on the detection surface, but has little influence on the RI; as the voltage rises, the faculae distribution on the detection surface becomes more obvious, and the mean of RI decreases. The above results have the reference value for the manufacture of GIL equipment and the research of PD optical detection. When the specular reflection coefficient of surface material is smaller and the diffuse reflection coefficient is larger, the outline of the light spot is clearer, the proportion of brighter parts is larger, and the maximum value of the RI is larger.


1979 ◽  
Vol 5 (4) ◽  
pp. 223-226 ◽  
Author(s):  
E. Dobierzewska-Mozrzymas ◽  
F. Warkusz

The resistivity of monocrystalline Al films was measured and compared with the resistivity calculated in terms of the function which takes into account both the external and the internal size effects. A comparison of the theoretical and experimental curves shows that the specular reflection coefficient (p) is small, while the coefficient of electron transmission through the grain boundary (r) increases with increasing film thickness.


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